Using Fanuc Subprograms.

I di d lot of CNC training in shops around Detroit a few years ago and almost all partprints were in metric.
Almost every shop converted the dimensions to inches and all nice and even metric numbers became really odd inch numbers.
So if you c/drilled, drilled and tapped a bunch of holed, you created a good chance for misalignment.
So here is what I did, by the way, this is from my website, www.doccnc.com.
Fanuc Sub example:

We want to C/Drill, Drill and Tap a series of holes, all are located at odd dimensions, we will drill 1 hole and put all hole locations into a sub for recall.
Advantage: You only have to program locations once and recall Sub.

More important: You can not make a mistake in hole locations, check out the C/Drill positions and you can be sure the drill, tap, will be exactly in the same location.

Note: Especially useful when dimensions are converted from Metric and every Inch dimension is a really odd number.
Example:
O100
N1 G90 G80 G40
T1 M6
G54 G0 X1.0 Y1.0 S1000 M3
G43 H1 Z1.0 M8
G81 G99 R.1 Z-.25 F5.0 (C/Drill 1st. hole.)
M98 P1000 (Jump to Sub O1000 for other locations.)
G91 G28 Z0 M9
M30



Sub: O1000
X2.093
X3.1229
X4.0327
Y1.1175
X.3214
G80 M9
M99 (Return to Main Program)

Drill 1st. hole, then recall Sub, same for chamfering, tapping, etc.